International audienceIn the frame of its research work on nuclear fuel safety, the French “Institut de Radioprotection et de Sûreté Nucléaire” (IRSN) has highlighted the importance of cladding tube oxidation on its thermomechanical behavior. The occurrence of radial cracking and spallation has been observed as the main mechanisms for the zirconia layer degradation during transient experiments. A study of these two mechanisms has been jointly launched by IRSN and Areva-NP. Thus laboratory air oxidations of fully recrystallized or stress-relieved low-tin Zircaloy-4 cladding tubes have been performed. Representative oxide layer thicknesses varying from 10 to 100 0m have been obtained. SEM micrographs of the obtained oxidised samples show that...